The gruesome discovery was made around 9:30 a.m. in the 8000 block of Reseda Boulevard, Jovel said.
Police said initial reports suggested the children had been stabbed to death, but no official cause of death has been released.
Jovel said investigators were still working to determine a motive.
The department received reports Carrillo was driving her car and heading north on Interstate 5 when she got in an altercation in the Bakersfield area. She abandoned her car and carjacked another vehicle, Jovel said.
Carrillo was detained in the Ponderosa area of Tulare County, about 100 miles (160 kilometers) north of Bakersfield, police said.
“At this point, she is a suspect in this incident but that doesn’t exclude other people,” Jovel said.
Lupe Cuevas, a neighbor of Carrillo and her children, told the San Bernardino Sun that she interacted with the three children and their grandmother during afternoon walks around the neighborhood.
One of the children, a girl, was drawn to her Chihuahua, Rosie, Cuevas told the newspaper.